Field of the Invention
The present invention relates to a contactless power transmission device and a power transfer system, and more particularly to a power control technique in a contactless power transmission device that transmits electric power to a power reception device in a contactless manner.
Description of the Background Art
Japanese Patent Laying-Open No. 2014-207795 discloses a contactless power feeding system that supplies electric power from a power feeding device (power transmission device) to a vehicle (power reception device) in a contactless manner. In this contactless power feeding system, the power feeding device includes a power transmission coil, an inverter and a control unit. The power transmission coil transmits electric power to the power reception coil mounted on the vehicle in a contactless manner. The inverter produces an AC current in accordance with a drive frequency for output to the power transmission coil. The control unit obtains a charging power command for a battery and output power for the battery from the vehicle side, and controls by feedback the drive frequency of the inverter such that the output power follows the charging power command. Japanese Patent Laying-Open Nos. 2013-154815, 2013-146154, 2013-146148, 2013-110822, and 2013-126327 also disclose techniques about contactless power transmission.